feat: major project restructure - move Django to backend dir and fix critical imports

- Restructure project: moved Django backend to backend/ directory
- Add frontend/ directory for future Next.js application
- Add shared/ directory for common resources
- Fix critical Django import errors:
  - Add missing sys.path modification for apps directory
  - Fix undefined CATEGORY_CHOICES imports in rides module
  - Fix media migration undefined references
  - Remove unused imports and f-strings without placeholders
- Install missing django-environ dependency
- Django server now runs without ModuleNotFoundError
- Update .gitignore and README for new structure
- Add pnpm workspace configuration for monorepo setup

tests/e2e/cleanup.sh

@@ -1,25 +0,0 @@
-#!/bin/bash
-set -e  # Exit on error
-
-echo "Cleaning up test data..."
-
-# Run Django cleanup command
-uv run manage.py cleanup_test_data
-
-# Clean up test fixtures
-echo "Cleaning up test fixtures..."
-rm -f tests/fixtures/test_photo.jpg
-rm -f tests/fixtures/test_avatar.jpg
-
-# Clean up Playwright artifacts
-echo "Cleaning up Playwright artifacts..."
-rm -rf test-results/
-rm -rf playwright-report/
-
-# Clean up pytest cache
-echo "Cleaning up pytest cache..."
-rm -rf .pytest_cache/
-rm -rf tests/e2e/__pycache__/
-find . -type d -name "__pycache__" -exec rm -r {} + 2>/dev/null || true
-
-echo "Cleanup complete!"